samples/common/include/Thread.h

/*
 * Copyright 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include "swappy/swappy_common.h"

#include <cstdint>
#include <unordered_map>
#include <mutex>

// Enable thread safety attributes only with clang.
// The attributes can be safely erased when compiling with other compilers.
#if defined(__clang__) && (!defined(SWIG))
#define THREAD_ANNOTATION_ATTRIBUTE__(x)   __attribute__((x))
#else
#define THREAD_ANNOTATION_ATTRIBUTE__(x)   // no-op
#endif

#define GUARDED_BY(x) \
  THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))

#define REQUIRES(...) \
  THREAD_ANNOTATION_ATTRIBUTE__(requires_capability(__VA_ARGS__))

namespace samples {

enum class Affinity {
    None,
    Even,
    Odd
};

int32_t getNumCpus();

void setAffinity(int32_t cpu);

void setAffinity(Affinity affinity);

// This is a minimal demonstration of a thread manager that uses pthreads.
// It is not intended for production use!
struct ThreadManager {
    std::mutex threadMapMutex;
    std::unordered_map<SwappyThreadId,pthread_t> threads;
    ThreadManager() {}
    ThreadManager(const ThreadManager&) = delete;
    static std::atomic<SwappyThreadId> nextId;
  public:
    static ThreadManager& Instance();
    int Start(SwappyThreadId* thread_id, void* (*thread_func)(void*), void* user_data);
    void Join(SwappyThreadId thread_id);
    bool Joinable(SwappyThreadId thread_id);
};

}